Photoelectric weft detecting means



July 7, 1964 M. BREITMEIER PHOTOELECTRIC WEFT DETECTING MEANS 2 Sheets-Sheet 1 Filed Sept. 12, 1960 lOl l lag' llllllllllllllll||IIIIHIIIIIllllllllllllllllilllllllllllllllll@ 3A la [N VEN T OR.

MAX BREIHEIER. B Y

A TT ORNE Y July 7, 1964 M. BREITMEIER PHOTOELECTRIC WEFT DETECTING MEANS 2 Sheets-Sheet 2 Filed Sept. 12, 1960 Fig. 7

2@ 24 23 [N VEN TOR. MAX BREIMEIER BY i12/MWL mama/J A TTORNE Y United States Patent O 3,139,911 PHTOELECTRIC WEFT DETECTING MEANS Max Breitmeier, Goldacirerweg 14, Zurich 9/ 47, Switzerland Fiied Sept. 12, 1960, Ser. No. 55,398 Claims priority, application Switzerland Sept. 14, 1959 Claims. (Cl. 139-370) The present invention relates to a novel method of and means for detecting thread breakages in textile machines and the like, and is particularly suitable for detecting weft breakages in weaving looms.

In order to avoid as far as possible faults in woven fabric and costly stoppages of Weaving looms, the weft thread must be observed throughout the weaving operation. On the one hand, it must be determined at each introduction of weft whether the weft thread has broken during its introduction, while on the other hand it must be possible to determine when the cop of weft in the shuttle is exhausted if no special cop feeler is provided. In both cases, the loom must be stopped immediately in order to prevent it from continuing to operate without any introduction of weft. If such a weft detecting device is not provided, the entire weaving operation must be observed by a weaver. This means that each weaver can operate only one loom, and the inspection and watching of the weft thread is unsatisfactory owing to human fallibility, This results in faulty goods and long loom stoppages.

Prior art arrangements for automatically observing the weft thread, generally called thread or central weft stop motions, have long been known. The principle of these arrangements resides in measuring the tension of the wett thread with the aid of a mechanical feeler or sensing member. In such cases, it is assumed that the broken weft thread either has no tension or has substantialy lower tension then the unbroken thread. The feeler usually consists of a fork-like or needle-like structure, which is rockably mounted on a pivot. At each passage of the shuttle, this feeler performs a rocking movement and thus moves into the range or path of the weft thread. If the weft thread is intact, the rocking movement of the feeler is stopped, so that a pawl system actuated by said feeler does not engage. On the other hand, if the weft thread is broken, the feeler can complete its rocking movement, because it does not encounter the necessary resistance of a tensioned thread. In this case, the pawls engage and stop the loom in known manner through a lever system. An exhausted cop produces the same effect on the feeler as a broken weft thread, because here again the weft thread is no longer tensioned.

The principle hitherto employed has the great disadvantage that contact with the weft thread is necessary for the detection. In the case of fine weft materials, this may directly result in thread breakage, In the case of extremely fine yarns, this system is entirely inapplicable owing t0 the low thread tension. In addition, certain types of fabric require such a loW weft thread tension that detection by means of mechanical contact with the weft thread is also impossible.

In the case of the weaving of decorative materials, it often happens that the weft material becomes caught in the weft feeler fork owing to its particular structure, s0 that said fork may become directly woven in the material or may otherwise spoil costly materials. If weft yarns of differing quality are woven on a loom, which is almost always the case with brocade looms for decorative materials and the like, it is impossible to so adjust the mechanical feeler that it satisfactorily responds to all yarn qualities. This is because yarns of different qualities must be woven-in with entirely different thread tensions owing to differing resistance to movement as they are pulled from the weft cop.

All these disadvantages, which may arise individually or collectively, have the attendant result that a weft stop motion cannot be employed precisely in cases in which the danger of weft breakages is greatest and in which stoppages in production and damage to fabric are most costly. Moreover, automation in most types of weaving looms is impracticable without automatically acting weft stop motions.

The characteristic feature of the method of the present invention resides in that, at a predetermined instant in relation to the angular position of the crankshaft or to the position of the batten, the presence of the weft thread in the position which it should occupy at this instant between the shuttle and the edge of the fabric is tested without contact. The main difference as compared with the hitherto employed methods using mechanical feelers thus resides in that the desired position of the weft thread inside or outside the shed can be checked without contact at a predetermined instant. The invention also concerns an apparatus for carrying out the said method, which apparatus is characterised by means disposed along the desired position of the weft thread for ascertaining without contact whether the weft thread is present in this desired position at said predetermined instant.

Accordingly it is an important object of the present invention to provide a novel method of and means for detecting thread breakages and exhaustion thereof without necessitating actual physical contact with said thread.

It is another important object of the present invention to provide a novel method of and means for sensing the non-presence of thread and the like in timed relation to its prescribed trajectory.

A further object of the present invention is the detection and sensing of undesirable operating conditions of a textile machine and the like without requiring actual contact with the threads or fabrics handled.

Still another object of the present invention is to provide means which positively detect the non-presence of threads and the like in reliance upon the normal movement of said thread in a predetermined path of travel and during a xed time interval.

These and still further objects of the present invention and its entire scope and applicability Will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spriit and scope of the invention will become apparent to those skilled in the art from this detailed description.

In the drawings:

FIGURE 1 diagrammatically illustrates the situation on a weaving loom with the weft thread intact,

FIGURE 2 shows the situation when the weft thread is broken,

FIGURES 3 to 6 illustrate examples of detecting means for carrying out the method according to the invention,

FIGURE 7 schematically illustrates a control system for shutting off the textile machine if non-presence of thread occurs.

Referring now to the drawings, in FIGURE 1 there is illustrated a diagrammatic view of a weaving loom taken from above. In the illustrated situation, the shuttle 1 moves along the batteri 2 from left to right and thus introduces the weft thread 5 into the warp 3. Owing to its longitudinal movement, and the simultaneous movement of the hatten 2 in the direction of the arrows B, the shuttle describes a curve 6 in space, the weft thread 5 thus being caused to pass the point A at a particular instant. Two shuttle positions shortly before and after this instant are ice shown in phantom. The desired position of the weft thread at the various instants is determined by an edge of the fabric 4 and by the thread outlet aperture 1a in the shuttle 1. The position of the shuttle 1 on the batten 2 is always the same with the same angular position of the driving crankshaft 2a (FIGURE 7) and the same position of the batten, i.e., the weft thread 5 should be in a predetermined position at each instant and in each angular position of the crankshaft. Situated at the point A is a detecting member acting without contact with the thread, which determines at each pick whether the weft thread 5 is present at the point A at the appropriate instant. If this is in fact the case, this is an indication that the weft thread is intact and unbroken, and that the weft thread is functioning properly.

FIGURE 2 shows the same situation as FIGURE l, but with the weft thread 5 broken. Depending upon the instant of the breakage of the weft thread, the latter will occupy a position indicated in FIGURE 2. In any event, no further thread will be drawn from the weft cop, and any thread remaining on the shuttle 1 Will be pulled behind said shuttle with a certain rigidity owing to the speed of the shuttle. In any case, however, the weft thread will not travel past the point A, because the connection from the edge 4 of the fabric to the outlet aperture 1a of the shuttle 1 is interrupted. The detecting member acting without contact will thus be unable to record any thread at a particular instant at the point A in this pick, which will be a certain indication of thread breakage or of an exhausted cop. This means that the loom or like machine must be stopped, which can readily be automatically controlled by the detecting member.

The position of the point A in FIGURE 1, which defines the operating or working Zone of the detecting means, along a particular desired position of the weft thread can to a large extent be freely chosen in accordance with the type of loom. The detecting member can therefore be disposed inside or outside the path of the fabric. In the case of looms simultaneously producing two webs of fabric, the detecting member can be disposed between the two webs. If, for reasons of space, the point A cannot be located at the center of the path of the fabric, it is necessary to dispose a detecting member on either side of the path of the fabric in order that each pick may be tested, regardless of whether it comes from the left or from the right. Since a pick coming from the left corresponds to a pick coming from the right in regard to the angular position of the crankshaft 2a and the position of the batten 2, all considerations are applicable regardless of the location of the detecting member.

FIGURE 3 diagrammatically illustrates in cross-sectional view a contactless detecting member directed towards the desired operating position A, together with its transmitter 7 consisting of a source of rays 8 and an optical system 9 for concentrating the rays 10. Situated in the receiver 11 mounted on the opposite side of the desired operating position A is an emitter element 12, for example a light-sensitive semiconductor element in the case of the use of light rays, which in the event of fluctuations in the intensity of the bundle of rays transmits corresponding impulses to the electronic amplifier 13. The rays employed may consist of visible light or of ultraviolet, infra-red or corpuscular rays. The detecting or testing member tests for the presence of the weft thread 5 in its desired position at each pick at the instant corresponding to the point A. When the weft thread 5 intersects the bundle of rays at the point A, the intensity of the latter is so varied owing to an at least partial interruption that the emitter element 12 emits an impulse to the amplifier 13, which means that the weft thread is intact. The absence of such an impulse at the instant in question, on the other hand, indicates a broken weft thread. The amplifier 13 may control an electrical relay 14 or it may directly control an electromagnet, which in l this case stops the loom or machine through a stop mechanism provided in association with the latter.

Depending upon the construction of the electronic arnplifier 13, the bundle of rays may act continuously or intermittently. The supervisory impulse may be set up by the shuttle travelling past, for example by inductive means. The value of the impulse at the emitter element 12 will vary in accordance with whether a weft thread is or is not situated at the point A at the appropriate instant.

FIGURE 4 diagrammatically illustrates a detecting member in which a transmitter 7 and a receiver 11 are disposed on the same side of the desired position of the weft thread. The bundle of rays 10 is at least partially reflected by the weft threadyS travelling past the point A, whereby a part of the reflected beam again impinges on the emitter element 12 and initiates a process similar to that described with reference to FIGURE 3. The occurrence of an impulse at the appropriate instant again indicating an intact weft thread. This arrangement is particularly suitable for metal fabrics having bare weft threads.

FIGURE 5 diagrammatically illustrates a detecting member in which the transmitter 7 and the receiver 11 are combined on the same side of the desired position. The bundle of rays 10 is reflected in accordance with the principle of the autocollimator by a reflector 15 disposed on the opposite side of the desired position of the weft thread. A partially permeable mirror 16 situated in the path of the rays directs the reflected rays onto the emitter element 12. When the weft thread 5 travels through the path of the rays at the point A, which should take place as close as possible to the reflector 15 in the interest of an optimum discrimination ratio, the intensity of the bundle of rays at the instant corresponding to the desired position A is again so varied that a current impulse is applied to the amplifier 13 by the emitter element 12.

FIGURE 6 illustrates diagrammatically a detecting member constructed as a plate condenser. There exists between the two condenser plates 17 an electrical field, the value of which depends upon the dielectric between the two plates. When the weft thread S passes through the point A and consequently through the field space between the condenser plates at a predetermined instant, the dielectric constant of the condenser varies, which results in a variation of the intensity of the field. The current impulse thus generated passes directly to the amplifier 13, at which it is amplified and further transmitted as in FIGURE 3.

If the weft consists of ferromagnetic material, a magnetic field may be employed instead of the electrical field. In principle, the arrangement remains the same as in FIGURE 6, except that there is employed to test for the desired position of the weft thread, instead of a condenser having a variable dielectric, an inductive sensing member with an air gap of variable magnetic conductivity bridging the point A.

In FIGURE 7 there is shown a possible arrangement of a control circuit for stopping the machine upon breakage or exhaustion of the thread. To this end there is provided a suitable power source 20 in circuit with a control relay or the like 21 and a normally open contact 22 and a normally closed contact 23. A cam 24 carried by the crankshaft 2a is designed to close the normally open switch 22 every time the weft thread passes point A. If the weft is present at point A the amplifier 13 actuates the normally closed contact 23 to open the latter, the machine continuing to run in a normal manner. If, however, the weft is not present at point A, at the time the contact 22 is closed by the cam 24, the amplifier 13 does not actuate the contact 23 and it remains in closed condition to thereby complete a circuit through the relay 21 designed to shut off the machine or loom in any known manner, as for example, by cutting-off the power supply to the machine or deenergizing a suitable clutch or coupling. Similarly, the cam 24 can be further designed to actuate the transmitter 7 at the proper instant of time should the latter not be operating continuously.

The described method and arrangements have, as compared with those hitherto employed, the great advantage that the weft thread is tested without actual contact. Therefore, itis unnecessary to take into account the thread tension as is the case with mechanical testing means, and damage to the weft material is impossible. The electronic and optical means permit such a fine adjustment of the detecting member that the presence of even the very finest weft threads can be satisfactorily tested. If the detecting member is adjusted for use with the finest weft threads, all coarser yarns are also automatically correctly tested, because the yarn thickness only iniluences the value of the impulse, and the smallest impulse value is suiiicient for reliable operation. Therefore, adjustment to different yarn thicknesses and yarn qualities is unnecessary. It is thus possible to render operative an automatic weft stop motion in all cases where this has been impossible for the technical reasons described at the outset.

Having thus described the invention what is desired to be secured by United States Letters Patent, is:

l. A method of determining proper functioning of weft threads in looms, comprising the steps of moving weft thread through a plurality of warp threads and in a predetermined path of travel to assume a predetermined position at a given instant of time, and applying detecting means to said predetermined position at least at said given instant of time Without actually physically contacting said weft thread to determine the presence of said weft thread.

2. A method of determining proper functioning of weft threads in looms, comprising the steps of moving weft thread through a plurality of Warp threads and in a predetermined path of travel to assume a predetermined position at a given instant of time, applying detecting means responsive only to the presence of said weft thread to said predetermined position at least at said given instant of time and Without actually contacting said weft thread to determine the presence of said weft thread.

3. A method of detecting the presence of weft threads in looms for weaving fabrics, comprising the steps of moving weft thread drawn from a shuttle through a plurality of warp threads and in a predetermined path of travel by means of a rotatable crankshaft to assume a predetermined position at a given instant of time in direct relation to the position of said crankshaft, said predetermined position of said weft thread being between an edge of the fabric being woven and the shuttle, and applying detecting means to said predetermined position at least at said given instant of time Without contacting said weft thread to determine the presence of said weft thread.

4. In a loom for weaving fabrics a system for detecting the presence of weft threads at a predetermined position of weft thread travel, comprising means including a shuttle for moving weft thread through a plurality of Warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path .of travel and cooperable with a xed position along said path of travel through which said weft thread passes when suspended between an edge of the fabric being woven and the shuttle land when properly functioning to determine the presence of said weft thread without actual contact with said weft thread.

5. In a loom for weaving fabrics a system for detecting the presence of 'weft threads at a predetermined position of weft thread travel, comprising means including a shuttle for moving weft thread through a group of warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path of travel and cooperable With a fixed position along said path of travel through which said weft thread passes when suspended between an edge of the fabric being Woven and the shuttle and when properly functioning to determine the presence of said weft thread without actual contact with said thread, said detecting means including transmitter means for delivering a bundle of rays and receiving means for receiving said bundle of rays.

6. In a loorn for Weaving fabrics a system for detecting the presence of weft threads at a predetermined position of weft thread travel, comprising means including a shuttle for moving weft thread through a series of warp threads and in a predetermined path of travel in la timed sequence, and detecting means positioned remote from said path of travel and cooperable with a fixed position along said path of travel through which said weft thread passes during suspension between an edge of the fabric being Woven and the shuttle and when properly functioning to determine the presence of said weft thread without actual contact with said weft thread, said detecting means including transmitter means for delivering a bundle of rays and receiving means -for receiving said -bundle of rays, said transmitter means land said receiver means being disposed on opposite sides of said xed position.

7. In a loom for weaving fabrics a system for detecting the presence of weft threads at a predetermined position of weft thread travel, comprising means including a shuttle for moving weft thread through a plurality of warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path of travel and cooperable with a lixed position along said path of travel through which said weft thread passes when suspended ibetween an edge of the fabric being woven and the shuttle Iand when properly functioning to determine the presence of said weft thread without actual contact with said weft thread, said detecting means including transmitter means for delivering a bundle of rays and receiving means for receiving said bundle of rays, said transmitter means and said receiver means being disposed on the same side of said iixed position.

8. In a loom for weaving fabrics a system for detecting the presence of yweft threads at a predetermined position of weft thread travel, comprising means including a shuttle lfor moving weft thread through a plurality of warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path of travel and cooperable with a fixed position along said path of travel through which said weft thread passes when suspended between an edge of the fabric being woven and the shuttle and when properly functioning to determine the presence of said weft thread without contacting said weft thread, said detecting means including means for generating a field, said weft thread during passage through said xed position influencing said iield to thus determine presence of said weft thread.

9. In `a loom for Weaving fabrics a system for detecting the presence of weft threads at a predetermined position of weft thread travel according to claim 8, wherein said field is an electric field.

l0. In a loom for weaving fabrics a system for detecting the presence of weft threads at a predetermined position of weft thread travel according to claim 8, wherein said field is a magnetic iield.

1l. In a system for detecting the presence of weft threads at a predetermined position of weft thread travel, comprising means for moving Iweft thread through a plurality of warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path of travel and cooperable with a fixed position along said path of travel through which said weft thread passes when properly functioning to determine the presence of said weft thread without actual contact with said weft thread, said detecting means including transmitter means for delivering a bundle of rays and receiving means for receiving said bundle of rays, said weft thread during passage through said fixed position disturbing the intensity of said bundle of rays, to thereby generate a signal adapted to maintain norm-al operating conditions of said weft thread.

12. In -a system for detecting the presence of weft threads at a predetermined position of weft thread travel according to claim 11, wherein said weft thread reflects said bundle of rays to disturb the intensity thereof.

13. In la system for detecting the presence of weft threads at a predetermined position of weft thread travel according to claim 11, wherein said detecting means include a reecting member `for reflecting said bundles of rays disturbed by saidy weft thread to said receiving means.

14. In a system for detecting the presence of weft threads at a predetermined position of thread travel, comprising means for moving weft thread through a plurality of warp threads and in a predetermined path of travel in a timed sequence, and detecting means positioned remote from said path of travel and cooperahle with a fixed position along said path of travel through which said weft thread passes when properly functioning to determine the presence of said weft thread without actual contact with said weft thread, said detecting means including transmitter means for delivering `a bundle of rays and receiving means for receiving said bundle of rays, said receiving means including an emitter element, an amplifier in circuit with said emitter element, and a control circuit in registry with said amplifier yadapted to control operation of said moving weft thread, said weft thread during u passage through said fixed position disturbing the intensity of said bundle of rays to thereby generate ia signal via said emitter element through said `amplifier operable on said control circuit.

15. In a system for detecing the presence of weft threads at a predetermined position of weft thread travel according to claim 14, said control circuit including a normally closed contact, said generated signal opening said normally closed contact to maintain proper functioning of said weft thread.

References Cited in the tile of this patent UNITED STATES PATENTS 1,980,294 Ross et al Nov. 13, 1934 2,256,595 Metcalf Sept. 23, 1941 2,432,171 Payne Dec. 9, 1947 2,492,737 Dunn Dec. 27, 1949 2,522,101 Dion et al. Sept. 12, 1950 2,670,014 Hutchinson Feb. 23, 1954 2,711,093 Edelman et al. June 21, 1955 2,911,013 Howe Nov. 3, 1959 2,971,695 Sick Feb. 14, 1961 3,003,524 Metzler Oct. 10, 1961 3,053,139 Loepfe Sept. 11, 1962 FOREIGN PATENTS 1,125,100 France July 9, 1956 876,679 Germany July 8, 1949 931,820 Germany July 8, 1949 

1. A METHOD OF DETERMINING PROPER FUNCTIONING OF WEFT THREADS IN LOOMS, COMPRISING THE STEPS OF MOVING WEFT THREAD THROUGH A PLURALITY OF WARP THREADS AND IN A PREDETERMINED PATH OF TRAVEL TO ASSUME A PREDETERMINED POSITION AT A GIVEN INSTANT OF TIME, AND APPLYING DETECTING MEANS TO SAID PREDETERMINED POSITION AT LEAST AT SAID GIVEN INSTANT OF TIME WITHOUT ACTUALLY PHYSICALLY CONTACTING SAID WEFT THREAD TO DETERMINE THE PRESENCE OF SAID WEFT THREAD. 